The safe disposal and containment of radioactive waste has become a problem of increasing concern. Because the radioactive elements are often mixed with large quantities of non-radioactive and non-toxic materials, the quantity of radioactive waste greatly exceeds the quantity of radioactive elements in the waste. While it would be desirable, therefore, to separate the radioactive elements form the remaining materials, this is often impractical or prohibitively expensive, and therefore the entire waste must be disposed of as radioactive waste.
Present methods of disposing of this waste consist of the evaporation of water, if water is present, and encapsulation of the remaining solids in cement or glass. This method must be conducted at a fairly low temperature because some of the radioactive material, such as ruthenium oxides or fluorides, will volatilize at high temperatures. While this method will successfully encapsulate the waste, it is very energy intensive and costly.
Another method of encapsulating the raw waste, when the radioactive elements are dissolved in solution, is to remove the radioactive elements onto ion exchange resins. This effectively separates the radioactive substances from the water, but both the radioactive elements and dissolved non-radioactive ions are removed onto the ion exchange resin, and the resin itself must then be disposed of, which adds to the total quantity of solid waste. In addition, the high radioactivity breaks down the carbon-to-carbon bonds in the ion exchange resins and renders them useless long before their normal life expectancy. Also, some radioactive waste solutions are highly acidic, and the highly concentrated acid can also attack and break down an ion exchange resin.